Police searched the home of New England Patriots tight end Aaron Hernandez for nearly four hours today, with a dozen officers and canine units entering the sprawling house and searching the back yard and his white Audi SUV.

Hernandez is the subject of an arrest warrant drawn up on obstruction of justice charges based on the possible destruction of evidence in connection with the shooting death of his friend, ABC News has learned.

But as of late Friday, a warrant had been drawn up but yet not issued by the court, according to a spokesman for the Attleborough District Court, which covers Hernandez's town.

Numerous police vehicles, including local and state police, unmarked cars, and a Crime Scene Unit car, arrived at Hernandez' home at around 1:40 p.m.

About a dozen officers -- mainly plain clothes police -- went into the house, along with two canine units.

At one point a local locksmith company named Cobb's was called in and entered the home for a little while.

People from all over North Attleborough came by to watch the cops, either sitting on the curb across the street or driving slowly by. Little girls even gave the cops directing traffic some cold bottled water.

After 5 p.m., the officers left with car loads of unmarked bags, which may have contained evidence collected from the house.

Hernandez, who is believed to be in the house, was not seen from outside the entire time police were there.

Police sources told ABC News on Thursday that a major investigative tool -- the security system at Hernandez's home, which included video -- had been intentionally destroyed. His cell phone was handed over to police "in pieces," and appeared to have been smashed.

Police also want to know why a team of house cleaners were hired on Monday to scrub Hernandez's mansion, the sources said.

Evidence is mounting that Hernandez and the victim, Odin Lloyd, 27, a semi-pro football player, had been together at several nightclubs during the course of the weekend, including the night before Lloyd's body was found, several law enforcement sources told ABC News.

The star NFL player has not been ruled out as a suspect in Lloyd's murder, sources said, but the warrant does not include a murder allegation.

Hernandez returned to his home Friday evening, sitting in the backseat of a car driven by his lawyer.

Hernandez's attorney, Michael Fee, has not commented on the investigation but released a statement Thursday saying: "It has been widely reported in the media that the state police have searched the home of our client, Aaron Hernandez, as part of an ongoing investigation. Out of respect for that process, neither we nor Aaron will have any comment about the substance of that investigation until it has come to a conclusion."

Hernandez has been at the center of the investigation since Lloyd's body was found shot in the back of the head in a scrubby clearing of an industrial park roughly a mile from the Patriots star's $1.7 million mansion in North Attleborough, Mass., on Monday.

Lloyd was believed to have been killed sometime before dawn on Monday, although his body was not discovered until Monday evening by a teenage jogger.

Police are also investigating "other incidents of violence" that Hernandez is suspected of being involved in, two sources told ABC News.